4.19.2009

Level design is communication. The constructed space itself needs to communicate the player's options-- where they can go, what they can do, how to progress. If the space doesn't adequately convey useful information, the player is lost.

Some games have less of this sort of information to convey than others. The player can assume that in a very linear, tunnel-like game, continuing to move forward is always the way to progress. As long as the designer communicates which way is forward (which door the player must exit through to continue) then the player will not be lost. On the other end of the scale are open-world games. The designer must clearly landmark destinations in the world, and the mini-map can be relied upon to lead the player there.

What about a game that lies more in the middle, like BioShock? Open-construction levels that the player can freely navigate, but that are made up of smaller, enclosed individual spaces result in a sort of ant farm arrangement. How does the designer keep the player oriented, and give them the information they need to easily navigate from one side of the level to the other?

These are my personal observations having spent a lot of time examining the levels from BioShock, and not any kind official process or information. These points mostly refer to the core systemic levels of BioShock: Medical Pavilion, Neptune's Bounty, Arcadia/Farmer's Market, Fort Frolic, Hephaestus, Olympus Heights/Apollo Square, and Point Prometheus.

Hubs & spokes

The most common high-level organizational strategy is the hub and spoke-- a large, central space from which smaller, self-contained spaces radiate. A straightforward example of this is the Medical Pavilion hub. You'll remember it as the place you first find the work of Dr. Steinman, and fight your first Big Daddy. The pavilion itself is large and open, with exits to the dental wing, surgery wing, funeral parlor, and so forth split off of it to all sides. However, the space is large enough to be partitioned throughout so that only a couple of possible exits can be seen by the player at any given time, as not to overwhelm them with too many simultaneous options.

As the player passes through the hub, they choose one possible exit and explore the space beyond it. Once this spoke has been explored, the pavilion acts as a reorienting space-- the player may think "alright, I'm done with this area. How do I get to the other parts of the level?" They backtrack through the spoke arriving back at the pavilion, which is easily identifiable. At this point the player only has to walk around the outer edge of the hub space to find exits to the rest of the possible spokes.

In this arrangement, minor spaces are always closer to major spaces than they are to other minor spaces-- the player always passes through the hub to get to another spoke. The player never proceeds directly from spoke to spoke, getting lost without an identifiable anchor space to reorient themselves by. The terminal point of any small explorable space is always just a short lifeline away from the major anchor space.

Consider this in contrast to an even distribution of small spaces that are all interconnected: if the player is on the far side of the level and wants to return to the place they started, they must pass through a succession of small, evenly-weighted spaces to return there. How does the player know whether they're making progress? How do they keep from getting turned around? The player must essentially memorize how each spoke is connected to every other. Even distribution of space results in a labrynthine construction that works against the player's sense of direction. Hub and spoke construction guarantees that even if the player is wandering blindly they will soon arrive at a large, recognizable space they've seen at least once before, and can reset their navigation from there.

Of course, this all goes back to principles of design for real-world public spaces. A shopping mall is laid out in this way-- short hallways branch off of a central concourse so that the visitor is never far from a large, central space that connects back to all the other minor spaces radiating from it. In BioShock, this is may be most recognizable in Fort Frolic, a large shopping mall in Rapture. Two main concourses are connected by a single passthrough, and all the shops, theatres and attractions branch off of these two major anchor spaces. When the player arrives at a dead end while exploring the tobacco shop for instance, they need only wander back the way they came until they reach the central atrium, from which they are reoriented and all their other options are open-- the Fleet Hall theatre, the casino, the strip club, etc. In Hephaestus it's the circular walkways ringing Hephaestus Core; in Apollo Square it's the large central courtyard containing the gallows, and so on.

The player's comprehension of an open-construction level is like a lifeline trailing behind them. If there's no central reorienting space, the player has nothing to anchor their line to; if the minor spaces radiating out from the anchor are too convoluted or arbitrarily interconnected, the player's lifeline gets tangled and they have no idea how to get back to their anchor point. A successful open-construction level is one where the player can be confident that their lifeline will always lead them back 'home,' from which they can cast out again, safe to explore new territory without being left adrift.

11 comments:

The area of Bioshock that I remember being the most confusing spatially (and I've heard this echoed by others as well) was Arcadia/Farmer's Market. Do you think its layout relative to what you've described here might be part of that?

The Arcadia area didn't have a hub as much as a very large main corridor that much smaller areas branched off from. The Farmer's Market was too complex to be just a spoke, but seemingly not of enough import to be a hub. Yet the market did have some very complicated spokes even within it, especially the winery. And while all the other areas had self-contained objectives, the player is sent to the Farmer's Market to resolve a problem in Arcadia.

Do you think, give the much clear hub/spoke layout of the rest of game's areas, the layout of Arcadia/Farmer's Market was incongruous and thus caused confusion?

With all due respect to my esteemed colleague JP Lebreton, I think the spaces in Arcadia are more evenly distributed and twisted together than most other levels in the game. I've also definitely heard the feedback that it's very easy to get lost in Arcadia. It's maybe the only level I still have to use the map to navigate around when playing.

Great post! I've not read your blog before but consider me a subscriber. It would be interesting if you continued this thinking into other games.

Dead Space is a good example of a game with a confusing level layout. It has hubs and corridors, however they aren't laid out in the spoke system you describe above and as a result the levels feel both cramped and confusing. EA Redwood employ a navigation system in-game on a joystick press, which turns the player toward his destination and renders a blue line on the ground. I can't help feeling that it's an afterthought, a result of too many lost and confused focus testers. If they'd used a simpler and more intuitive layout they could have avoided the need for the navigation system.

Do you feel Bioshock needed the quest arrow? Unfortunately I didn't get very far through Bioshock as I didn't enjoy it (although I may go back soon), but I don't remember using the quest arrow much ... whereas in Dead Space I used it almost as much as I did my weapons!

Interesting article. I agree with Nels: Arcadia and the Market were the most confusing, or, at least, the spaces in which I was most aware of needing to check the map.

Do you think that the pressure a player is under (be it time or task) should also be considered when laying out a space? During most of "BioShock", I was free to explore, but the few times I was under pressure, it seemed that the designers had taken care to make the space easier to follow, to reduce the amount of back-tracking I would—and could—do.

For example, Point Prometheus, was very hub–spoke, but then the Proving Grounds were more tunnel-like. I felt that this was done so I could focus on protecting the little sister (sisters—I didn't do as well as I wanted to).

Great article! These principles were definitely in mind during the development of Bio1's maps. They came sharply into focus about halfway through production (mid-2006) and was one of the biggest reasons we rebuilt almost every space in the game around that time.

Thinking back on the many phases of its construction, I think the lesson of Arcadia is that you can't retro-fit this kind of top-down organization; you have to plan it from the start. Arcadia was originally built as a hive of differently themed areas (Tea Garden, Waterfall Grottos, etc), without the central connecting hallway. This was even worse for navigation, so the second major build of it added the central hallway.

However, each sub-area was enough of a unique maze in itself that we only really solved the highest level navigation issues. The Tea Garden, for instance, was really more of a linear dungeon than a tree-leaf structure because it came at the very beginning of the level and we felt the player should be threaded through a certain sequence of spaces to ensure strong, intentional pacing. What we ended up with though, I think, was "over-threaded"... there were too many contrived architectural twists and turns for the player to parse and landmark.

So interestingly, there is a soft tension between the demands of good traditional FPS pacing and the organizational logic of good semi-open spaces. This comes up again and again in BioShock 2's development.

After such a busy week of work, you'd think I'd be sick of thinking about it, but I guess not.

Great article! The hub/spoke level design is something that I think I've kind of picked up subconsciously (from Bioshock and other games), but it's good to have it consciously archived for future reference.

Great blog, Steve. As an utterly stone fan of Bioshock I'm just discovering the comments and articles in your blog, and this one was fascinating. For me, the tracking arrow was essential - since there was no map. If you were going to take away the arrow, the player would need to have a map. We players need to be intrigued and even challenged, but not mystified to the point of confusion.

As to what JP said about Arcadia - I really liked the odd, sprawl of its convolution. Not being able to solidly envisage it all your head adds to its value. I think I`ve played the game about 6/7 times now, straight through, and I still found a new way of approaching and playing it at the 7th.

I'm a writer, by the way, and as you might guess I was completely gripped by the narrative, or rather the double narrative: the narrative of the backstory, and the narrative of the action. I've expanded on these thoughts in my own blog.

(Slap forehead)...oh yeah, of course there was that map. I guess I didnt equate it with other naturalistic maps. Hm, yes. The Bioshock map I found needed a certain focus of attention to figure out/recall which areas the big swooping arrows connected to. Oh, I`m a PC guy, for my sins!